Treble Bleed Mod Round-up

Published Thursday, November 24, 2016 by DrKev

As a reference resource, I have collected the treble bleed capacitor and resistor combinations recommended by many major guitar pickup manufacturers (and some guitar makers too). I am reproducing that list here. Below the list I have also included notes and additional information based on my research and experience. I hope you find it useful. Feel free to contact me with any questions or suggestions.

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The Treble Bleed Modification List

(listed in order of increasing capacitor value, for no other reason than I have to choose something)
NB: Resistors are IN PARALLEL with their capacitor unless stated otherwise

Many thanks to everyone who has emailed with values that were not prviously on this list. It is greatly appreciated! If anyone has any other recommendations from other manufacturers to add, feel free to drop me a line and I’ll add it to the list!

tl;dr Rule of thumb: If you use a 10 ft cable from your guitar, choose the Mojo, DiMarzio, or Suhr values. If you use a 30 ft cable choose the TV Jones, Fender, or Seymour Duncan values. See note 6 below.

2: Treble bleed mod can have NO effect on your guitar tone when the volume pot is on 10 as the capacitor (and its resistor if present) are short circuited.

3: Guitars with active pickups or a buffer preamp onboard the guitar do not usually require a treble bleed mod.

4: The simplest treble bleed mod is to use a low value capacitor on it’s own. For many people this may not be particularly satisfactory – the tone of your guitar may become noticeably or even horribly bright as you roll down the volume (the opposite of the original problem). However, an advantage of the single capacitor option is that the taper of the volume pot does not change, i.e. the change in volume across the sweep of the volume pot is unchanged from the stock un-bypassed state.

PRS guitars actually choose this approach, and install a 180 pF bypass cap as standard on many of their guitars (usually with humbuckers and 500 kΩ volume and tone pots).

The Gibson “50’s wiring” can have a similar effect to a lone capacitor (some suggest even more neutral) BUT the effect of the guitars volume and tone controls are now interactive (e.g. the tone control can produce changes in volume) which some people find to be a drawback.

5: Adding a resistor in parallel with a larger value capacitor helps to keep the guitar tone more balanced as the volume pot is decreased and corrects the issue of too much treble from a lone capacitor. The lower the value of this bypass resistor, the less the capacitor passes treble at low volume settings. Conversely, the higher the value of the resistor, the more treble is passed by the capacitor.

However, a parallel resistor affects the taper of the volume pot. This results in a more gradual change of volume across the range of the volume knob (i.e. it will give you less volume change between 10 and 7 and a faster volume change between 1 and 3). Personally, I am long used to this and find un-altered circuits change volume too drastically without it. Volume swells can be less smooth at the lowest numbers on the volume knob, particularly for high gain players. No such thing as a free lunch, eh? Everything is a compromise, all the time. Some of this change can addressed with the Fender mod of adding an additional series resistor in the 20 kΩ to 50kΩ range. (see note 6 below).

For those of you who don’t like how the parallel mod affects the volume pot taper, and the volume changes too slowly for your liking, a capacitor and resistor in series (e.g Chris Kinman‘s mod) gives a less drastic change in volume taper but the tone of the guitar may changes in a different way as the volume pot is turned down. This series combination passes a little more midrange than the equivalent parallel circuit. It feels a little like dialing back the bass and treble a touch. You may or may not notice this tonal difference between parallel and series resistors, you may prefer one over the other, and may prefer the taper change of one over the other, so feel free to experiment and let your ears tell you what works best for you.

When testing, if possible, do A-B recordings (even the voice recorder on your phone is useful for this) and try to use the same volume settings on the guitar. Stratocaster style volume knobs are useful here but a small piece of tape and marker can be useful on knobs without numeric markings.

6: The capacitor/resistor values that work best for you will generally depend on your total cable capacitance, which is related to the total length of cable your guitar. That in mind, and based on my circuit modelling, my current rule of thumb is as follows:

If you use a 10 ft cable from your guitar, choose the Mojo Tone, DiMarzio, or Suhr values. If you use a 30 ft cable choose one of the versions with 1 nF or 1.2 nf capacitor.

You may have to experiment to achieve what your ears will regard as the perfect combination for your setup. But that’s just not that easy to do for most people nor a particularly efficient use of time. The good news is that most people who are bothered by the loss of treble at lower volume pot settings will be very happy with many of the above choices. If the result is too bright choose a larger value capacitor (and a lower value if the result is too dark). But the values are not particularly critical because of the lack of sensitivity of our ears to some of the differences between the choices above, and the fact that when playing real music we don’t pay attention to those kind of details. You don’t have spend time trying to figure out what the perfect choice might be, just dive in.

Incidentally these values (1 nF & 150 kΩ) are sold by Stew Mac as a their “Golden Age Treble Bleed Circuit”.

Fender have recently marketed a “Tone Saver” that they sometimes claim is not a simple treble bleed circuit, sometimes claim is a simple treble bleed circuit. but when cut open features, can you guess? Yep, a 1.2 nF cap and a 130 kΩ resistor in a fancy package that costs 10 times more than the practically identical Stew Mac product. Shame on you Fender! Almost as expensive as a Gibson fake bumblebee cap (see note no 9 below).

Interestingly though, in Fender‘s current American professional series guitars they have a new combination, which is a 1.2nF cap, 130kΩ parallel resistor, and a 20kΩ series resistor. The extra little series resistor is interesting. Without we can already maintain the resonant frequency and peak height with standard parallel bypass components. This extra series resistor doesn’t make much difference tonally (because most of the above noted values already do a good job without it and the ear won’t be very sensitive to the differences). But it does restore some of the change in the taper of the volume pot closer to it’s stock characteristics.

Personally, in my Silhouette Special (HSS with 250 kΩ volume and tone pots) I currently like the DiMarzio cap value of 560 pF with a 150 kΩ parallel resistor.In my circuit simulations, this combination also produced the smallest change in volume pot taper of any of the parallel resistor/capacitor combinations (though it is still a very noticeable change). With a Planet Waves 10ft cable, depending on which effects pedals I am connected to it is either tonally neutral to my ears or introduces a slight but pleasant increase in brightness at low volume pot settings. I don’t think I can improve on this with such a simple circuit.

7: Pickup maker Jason Lollar recommends no treble bleed at all but suggests a smaller value tone cap or even Gibson 50’s tone pot wiring. He has stated that even with the volume knob on 10 the treble bypass circuit will affect your tone. But his statements are completely contrary to long time tried-and-tested basic electronics knowledge. True, some people prefer the Gibson/50’s tone pot mod. But a smaller value cap on the tone pot has no bearing on treble loss at low volume pot settings if you use standard wiring. And, as the bypass cap/resistor are completely short circuited when the volume pot is on 10 they cannot have any effect on the circuit or your tone. I suggest you ignore Lollar’s statements on this particular subject.

8: The construction of capacitor or resistor you use in passive audio frequency circuit can have NO bearing on the sound of your guitar. Let me repeat that another way – the type of capacitors and resistors you choose will have NO effect on the tone of your guitar. None, Zero, Zip, Nada, Zilch! The only thing that matters is the VALUE of the capacitor or resistor. If the values are identical, your ceramic/PIOs/Polys/Bumblebees/orange drops etc. will all sound exactly the same. I am not going to argue this point with any one. The basic physics of capacitors, i.e. how we know they really work, makes it absolutely clear that at audio frequencies this is the only way things can be. This will be the subject a future blog post!

You may have your personal favourites, for whatever reason, and that’s absolutely fine, but I assure you that if your brain tells you that you can hear a difference, it’s all down to expectation bias. Blinded A-B testing, e.g. from before-and-after recordings, will convince most people of this quite easily. i.e. when people don’t know what type of capacitor is being used, and are asked to pick which one is which, they are unable to tell the difference between different types (i.e. they get the answers right, and wrong, just as often as randomly picking an answer without listening).

It’s high time we stopped allowing vendors to sell horribly overpriced components on the basis of mythical characteristics that don’t actually exist. (Yes, Gibson, I’m looking at you, with your $100+ for a pair of fake bumble bee capacitors. Shameful!)

By all means, buy whatever components you like and are willing to spend money on if they will inspire you to play your guitar more often and get greater enjoyment from your music. Don’t let anyone tell you otherwise! But don’t believe that you’ll achieve vintage tonal nirvana because you allow yourself to be horrifically overcharged on what are the most basic and cheapest electronic components possible.

9: Guitar signals are tiny, the voltages involved are very small. This means that the voltage rating of the capacitors is of no importance. You can use whatever voltage rating you like but while higher voltage rating components are physically larger and little easier to handle, lower voltage rating caps are a better fit in tight spaces such as guitar control cavities.

Many thanks to all of you who emailed with comments! Your efforts are greatly appreciated!

Last updates: 12 Nov 2018: A few small edit and typos fixed. 27 November 2017: updated the Fender additional series cap information. 26 November, 2017: Added rule of thumb based on cable length. 15 November, 2017: Added new circuit (with additional series capacitor) found on Fender American Professional Series guitars. Added a comment on the Kinman series combination.

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